Container, more particularly for nitriding purposes



D ls, 93 v A. JfP. DUVAL 1,941,128

CONTAINER, MORE PARTICULARLY FOR NITRIDING PURPOSES Filed Jan. 7, 1930 looooooooe bo Fig.3.

Byway Patented Dec. 26, 1933 PATENT. OFFICE CONTAINER, MORE PARTICULARLY FOB NITRIDING PURPOSES Adrien Jules Pierre Duval, Paris, France, assignor to Aubert & Duval Freres, Paris, France Application January 7, 1930, Serial No. 419,029, and in Germany January 23, 1929 4 Claims.

The invention has for its object an improved containermore particularly intended to be used in the nitriding process.

The process of hardening steel or cast iron articles by nitriding has heretofore generally been carried out with the use of metallic containers of small or medium size for holding the articles to be-nitrided. Large containers have been open to the objection that the articles nim trided therein have not been uniformly hardened. The invention has for its object to provide a container for articles intended to be nl-= trided which will avoid the disadvantage of the containers heretofore used and which may be of any desired size and yet insure a uniform hardness in the articles treated therein. This object is achieved according to the invention by providing means for preheating the gas to a working temperature prior to its entrance into the container and for causing it to stream through the whole container in a uniformly distributed state.

In order that the invention can be more readily understood, an embodiment of the same is illustrated diagrammatically in the drawing by way of example in which drawing:

Fig. 1 is an elevation of a nitriding container,

Fig. 2 is a section on line 2-2 of Fig. l, and

Fig. 3 is a section on line 3-3 of Fig. l.

The nitriding container A is made from chromium-nickel steel platesof high percentage of chromium and nickel and is of rectangular shape and about square cross section. On the top it is closed by a cover B, Figs. 1 and 2, that can be secured thereon by means of screws, bolts or other suitable means. To the one longitudinal side of the container A is attached the gas supply which consists of pipes C, C having inserted between them a chamber C The chamber.

C contains a system of tubes 0 Fig. 2; through which passes the gas from pipe 0 to pipe C On the inner side of the longitudinal wall carrying the gas supply is provided a distributor which is formed by a box a fixed on this longitudinal wall and having the shape to be seen from the drawing. It, extends nearly down to the bottom of the container A and has on its lower wall a plurality of holes a On the opposite longitudinal gwall of container A isarranged a correspondingly shaped collector formed by a box a similar to the distributor box a but mounted inversely with respect to a It has holes a intendedto take in the gas that leaves the container A and provided on its top wall turned to- 55 ward the cover B. An exit gas pipe D is attached to the longitudinal wall carrying the collector which latter is'provided further with an aperture (not shown) for the introduction of a pyrometer.

To carry out the nitriding the container filled with the articles to be hardened is put into the furnace and the supply and outlet pipes are attached correspondingly. The nitriding gas then streams through the supply 0, C 0 to thedistributor a and is preheated in its passage through the supply and the distributor a to the desired nitriding temperature. Furthermore, a suitable degree of decomposition of the gasis 'produced in this way. The holes a of the distributor causethe nitriding gas to enter the container A in uniform distribution. On its way through the container A the gas circulates around the articles to be hardened in the container and then through the holes a into the collector a and from there to the outlet pipe D. The uniform distribution of the gas in the container effected by the distributor a and collector results in the articles to be hardened in the container being uniformly acted upon by the gas' current and thus hardened uniformly.

By the preheating of the gas and its uniform distribution in the nitrogenizing container the use of containers of any desired size is rendered possible as well as nevertheless a uniform hardening efiect.

Without deviating from the essence of the invention the tubes 0 arranged in the chamber C may be dispensed with and replaced by. metal filling pieces that ofier to the gas current an adequate great surface for. effecting the desired preheating of the gases and. their decomposition to that degree that will insure optimum results in the nitriding operation. Finally, the entire chamber C may be dispensed with provided that an adequate great inner surface. is ofiered to the gas current by the supply conduit C C What is claimed is:-

1. A container for nitriding adapted to be placed inand removed from a heating chamber and having a gas inlet, a gas outlet, 9. gas distributing chamber arranged along one side of the container in communication with the gas inlet, a gas-collecting chamber arranged along another side of the container in communication with the gas outlet, the gas-distributing chamber and the gas-collecting chamber being in free communication with the working space of the container along a substantial portion of their posite points of said container.

2. A container for nitriding adapted to be placed in a heating chamber and having a gas inlet, a gas outlet, means in communication with the gas inlet arranged to admit gas to the working space of the container adjacent the bottom and substantially along the entire length of one wall of the. container and means in communication with the gas outlet arranged to cause the gas to lea e the working space adjacent to the top and substantially along the entire length of the opposite wall of the container.

3. A container for nitriding adapted to be placed in a heating chamber and having a gasdistributing chamber arranged along one wall of the container and having apertures therein substantially along the length of said wall adjacent the bottom of the container, a gas-collecting chamber arranged along an opposite wall of the container and having apertures therein substantially along the length of said wall adjacent the top of the container, a gas inlet in communication with the distributing chamber and a gas outlet in communication with the collecting chamber.

4. A container for nitriding oi the class described comprising a relatively large enclosure having an inlet extending substantially along the length of one wall thereof, and an outlet extending substantially along the length of an opposite wall thereof, said enclosure in cross-section at right angles to said inlet and said outlet being substantially square, said inlet and outlet arranged substantially diagonally of said enclosure for causing nitrogen-containing gas passing through said enclosure-to stream through the entire enclosure in a substantially unitorm manner.

ADRIEN JULES PIERRE DUVAL. 

